A balance between supply and demand must be determined to meet the parking requirements of motorists. The ability to efficiently allocate and manage on-street parking remains elusive, even when parking requirements are significant, recurring, and known ahead of time. For instance, urban parking spaces characteristically undergo periods of widely skewed demand and utilization, with low demand and light use in some periods, often during the night, and heavy demand and use at other times. Real-time parking occupancy detection systems are an emerging technology in parking management.
Some prior art parking occupancy detection approaches utilize a puck-style sensor configuration that outputs a binary signal when detecting a vehicle in, for example, a parking stall or a particular parking spot. FIG. 1, for example, illustrates respective parking occupancy detection systems 100 for parking occupancy detection in an on-street parking. In the example depicted in FIG. 1, system 100 includes one or more puck-style in-ground sensors 102, 104, 106. Also depicted in FIG. 1 are example parking spaces 110, 108, 112, 114. A vehicle 116 is shown parked in parking space 108 in FIG. 1. The vehicle 116 can be detected by a sensor similar to 102, 104, and 106 located in parking space 108 underneath the vehicle 116. In the example shown in FIG. 1, the sensors 102, 104, and 106 can provide real-time parking occupancy data
Video-based parking occupancy detection systems, an example of which is shown in FIG. 2, are a recently developed technology. The video-based parking occupancy detection system shown in FIG. 2, for example, generally includes an image-capturing unit 152 (e.g., a video camera) mounted on, for example, a pole 151. The image-capturing unit 152 monitors within its field of view one or more vehicles 154, 156, 158 respectively parked in parking spaces 160, 162, 164.
On-street parking occupancy data has many applications. In one example, parking occupancy data can aid drivers searching for the parking spots so that traffic congestion in cities due to drivers circling about parking lots in a wasteful and time consuming effort to find parking spots can be reduced. In another example, on-street/curbside parking space reservation systems have been proposed based on inputs from parking occupancy data. In yet another example, parking occupancy data can aid law enforcement agencies to locate parking violations when parking occupancy data is compared with parking meter payment data. In general, parking occupancy data obtained from parking occupancy detection systems is the base for parking space management and reservation systems.
The prior arts of parking occupancy data detection system, including the puck-style in-ground sensor in FIG. 1 and the video based parking occupancy detection system shown in FIG. 2 are not portable. The camera 152 for capturing video is typically installed on a fixed utility pole 151. Power has to be accessible on the street for the camera 152 and other components of the system. There are many situations where a portable solution is preferred. One example is that not all streets include utility poles, or if they do, power may not be accessible. Another example is the situation where parking occupancy can be processed offline to infer parking occupancy patterns over a day, a week or months. Under this circumstance, a portable solution is much more economical compared with the fixed camera solution as the portable solution can be rotated to use from street to street.
FIG. 3 illustrates an ultrasonic parking sensor system that includes one or more ultrasonic sensors 176, 178, 180 deployed, for example, in a ceiling of a parking garage with respect to parking spaces 171, 173, 175 in which respective vehicles 170, 172, and 174 are parked. Again, such a solution is not portable.